X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fmain%2FTidyPgm.lhs;h=82021b813384a30bf36c0c73318bd627b72cfe74;hp=24c2464378fca557ede022fd9b2e59035e56f3bb;hb=e79c9ce01d0ce4412bd4bcd99c8c728a6a2ec569;hpb=6ccd648bf016aa9cfa13612f0f19be6badea16d1 diff --git a/compiler/main/TidyPgm.lhs b/compiler/main/TidyPgm.lhs index 24c2464..82021b8 100644 --- a/compiler/main/TidyPgm.lhs +++ b/compiler/main/TidyPgm.lhs @@ -209,7 +209,7 @@ unit. These are This exercise takes a sweep of the bindings bottom to top. Actually, in Step 2 we're also going to need to know which Ids should be exported with their unfoldings, so we produce not an IdSet but an -ExtIdEnv = IdEnv Bool +IdEnv Bool Step 2: Tidy the program @@ -504,12 +504,10 @@ getImplicitBinds type_env %************************************************************************ \begin{code} -type ExtIdEnv = IdEnv Bool - -- In domain => Id is external - -- Range = True <=> show unfolding, - -- Always True for InlineRule - -findExternalIds :: Bool -> [CoreBind] -> ExtIdEnv +findExternalIds :: Bool + -> [CoreBind] + -> IdEnv Bool -- In domain => external + -- Range = True <=> show unfolding -- Step 1 from the notes above findExternalIds omit_prags binds | omit_prags @@ -549,7 +547,8 @@ addExternal (id,rhs) needed -- "False" because we don't know we need the Id's unfolding -- Don't override existing bindings; we might have already set it to True - new_needed_ids = (mb_unfold_ids `orElse` emptyVarSet) `unionVarSet` + new_needed_ids = worker_ids `unionVarSet` + unfold_ids `unionVarSet` spec_ids idinfo = idInfo id @@ -557,25 +556,29 @@ addExternal (id,rhs) needed loop_breaker = isNonRuleLoopBreaker (occInfo idinfo) bottoming_fn = isBottomingSig (newStrictnessInfo idinfo `orElse` topSig) spec_ids = specInfoFreeVars (specInfo idinfo) + worker_info = workerInfo idinfo -- Stuff to do with the Id's unfolding + -- The simplifier has put an up-to-date unfolding + -- in the IdInfo, but the RHS will do just as well + unfolding = unfoldingInfo idinfo + rhs_is_small = not (neverUnfold unfolding) + -- We leave the unfolding there even if there is a worker -- In GHCI the unfolding is used by importers - show_unfold = isJust mb_unfold_ids - - mb_unfold_ids :: Maybe IdSet -- Nothing => don't unfold - mb_unfold_ids = case unfoldingInfo idinfo of - InlineRule { uf_worker = Just wkr_id } -> Just (unitVarSet wkr_id) - InlineRule { uf_tmpl = rhs } -> Just (exprFreeIds rhs) - CoreUnfolding { uf_guidance = guide } - | not bottoming_fn -- Not necessary - , not dont_inline - , not loop_breaker - , not (neverUnfoldGuidance guide) - -> Just (exprFreeIds rhs) -- The simplifier has put an up-to-date unfolding - -- in the IdInfo, but the RHS will do just as well - - _ -> Nothing + -- When writing an interface file, we omit the unfolding + -- if there is a worker + show_unfold = not bottoming_fn && -- Not necessary + not dont_inline && + not loop_breaker && + rhs_is_small -- Small enough + + unfold_ids | show_unfold = exprSomeFreeVars isLocalId rhs + | otherwise = emptyVarSet + + worker_ids = case worker_info of + HasWorker work_id _ -> unitVarSet work_id + _otherwise -> emptyVarSet \end{code} @@ -632,7 +635,8 @@ findExternalRules binds non_local_rules ext_ids tidyTopBinds :: HscEnv -> Module -> TypeEnv - -> ExtIdEnv + -> IdEnv Bool -- Domain = Ids that should be external + -- True <=> their unfolding is external too -> [CoreBind] -> IO (TidyEnv, [CoreBind]) @@ -671,7 +675,8 @@ tidyTopBinds hsc_env mod type_env ext_ids binds tidyTopBind :: PackageId -> Module -> IORef NameCache -- For allocating new unique names - -> ExtIdEnv + -> IdEnv Bool -- Domain = Ids that should be external + -- True <=> their unfolding is external too -> TidyEnv -> CoreBind -> IO (TidyEnv, CoreBind) @@ -794,7 +799,7 @@ tidyTopPair ext_ids rhs_tidy_env caf_info name' (bndr, rhs) rhs' = tidyExpr rhs_tidy_env rhs idinfo = idInfo bndr idinfo' = tidyTopIdInfo (isJust maybe_external) - idinfo unfold_info + idinfo unfold_info worker_info arity caf_info -- Expose an unfolding if ext_ids tells us to @@ -802,21 +807,9 @@ tidyTopPair ext_ids rhs_tidy_env caf_info name' (bndr, rhs) -- True to show the unfolding, False to hide it maybe_external = lookupVarEnv ext_ids bndr show_unfold = maybe_external `orElse` False - unfold_info | show_unfold = tidyUnfolding rhs_tidy_env rhs' (unfoldingInfo idinfo) + unfold_info | show_unfold = mkTopUnfolding rhs' | otherwise = noUnfolding - -- NB: do *not* expose the worker if show_unfold is off, - -- because that means this thing is a loop breaker or - -- marked NOINLINE or something like that - -- This is important: if you expose the worker for a loop-breaker - -- then you can make the simplifier go into an infinite loop, because - -- in effect the unfolding is exposed. See Trac #1709 - -- - -- You might think that if show_unfold is False, then the thing should - -- not be w/w'd in the first place. But a legitimate reason is this: - -- the function returns bottom - -- In this case, show_unfold will be false (we don't expose unfoldings - -- for bottoming functions), but we might still have a worker/wrapper - -- split (see Note [Worker-wrapper for bottoming functions] in WorkWrap.lhs + worker_info = tidyWorker rhs_tidy_env show_unfold (workerInfo idinfo) -- Usually the Id will have an accurate arity on it, because -- the simplifier has just run, but not always. @@ -840,9 +833,9 @@ tidyTopPair ext_ids rhs_tidy_env caf_info name' (bndr, rhs) -- unfoldings, which are inside Ids imported by GHCi. Ditto RULES. -- CoreToStg makes use of this when constructing SRTs. tidyTopIdInfo :: Bool -> IdInfo -> Unfolding - -> ArityInfo -> CafInfo + -> WorkerInfo -> ArityInfo -> CafInfo -> IdInfo -tidyTopIdInfo is_external idinfo unfold_info arity caf_info +tidyTopIdInfo is_external idinfo unfold_info worker_info arity caf_info | not is_external -- For internal Ids (not externally visible) = vanillaIdInfo -- we only need enough info for code generation -- Arity and strictness info are enough; @@ -858,19 +851,32 @@ tidyTopIdInfo is_external idinfo unfold_info arity caf_info `setAllStrictnessInfo` newStrictnessInfo idinfo `setInlinePragInfo` inlinePragInfo idinfo `setUnfoldingInfo` unfold_info + `setWorkerInfo` worker_info -- NB: we throw away the Rules -- They have already been extracted by findExternalRules ------------- Unfolding -------------- -tidyUnfolding :: TidyEnv -> CoreExpr -> Unfolding -> Unfolding -tidyUnfolding tidy_env _ unf@(InlineRule { uf_tmpl = rhs, uf_worker = mb_wkr }) - = unf { uf_tmpl = tidyExpr tidy_env rhs, - uf_worker = fmap (tidyVarOcc tidy_env) mb_wkr } -tidyUnfolding _ tidy_rhs (CoreUnfolding {}) - = mkTopUnfolding tidy_rhs -tidyUnfolding _ _ unf = unf +------------ Worker -------------- +tidyWorker :: TidyEnv -> Bool -> WorkerInfo -> WorkerInfo +tidyWorker _tidy_env _show_unfold NoWorker + = NoWorker +tidyWorker tidy_env show_unfold (HasWorker work_id wrap_arity) + | show_unfold = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity + | otherwise = NoWorker + -- NB: do *not* expose the worker if show_unfold is off, + -- because that means this thing is a loop breaker or + -- marked NOINLINE or something like that + -- This is important: if you expose the worker for a loop-breaker + -- then you can make the simplifier go into an infinite loop, because + -- in effect the unfolding is exposed. See Trac #1709 + -- + -- You might think that if show_unfold is False, then the thing should + -- not be w/w'd in the first place. But a legitimate reason is this: + -- the function returns bottom + -- In this case, show_unfold will be false (we don't expose unfoldings + -- for bottoming functions), but we might still have a worker/wrapper + -- split (see Note [Worker-wrapper for bottoming functions] in WorkWrap.lhs \end{code} %************************************************************************